.page-about {
  --about-card: #FBF7ED;
  --about-body-ink: rgba(16, 22, 28, .78);
  --about-body-paper: rgba(244, 239, 227, .8);
  display: block;
  background: var(--paper);
  color: var(--black);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--ink-900);
  color: var(--paper);
  padding: 24px 0 56px;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 36%;
  height: 1px;
  background: var(--amber);
  opacity: .75;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -42%;
  right: -24%;
  width: 62%;
  height: 186%;
  background: linear-gradient(180deg, rgba(18, 49, 74, .96) 0%, rgba(18, 49, 74, 0) 74%);
  transform: rotate(16deg);
  pointer-events: none;
}

.page-about .about-hero > .container {
  position: relative;
  z-index: 1;
}

.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .06em;
  color: var(--slate);
}

.page-about .breadcrumb a {
  color: var(--slate);
  text-decoration: none;
}

.page-about .breadcrumb a:hover {
  color: var(--amber);
}

.page-about .breadcrumb [aria-current="page"] {
  color: var(--amber);
}

.page-about .crumb-slash {
  color: var(--slate);
  opacity: .6;
}

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
  margin-top: 38px;
}

.page-about .about-hero-head .eyebrow {
  margin: 0;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .22em;
  color: var(--amber);
}

.page-about .about-hero h1 {
  margin: 16px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 38px;
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--paper);
}

.page-about .about-hero .lede {
  margin: 0;
  max-width: 58ch;
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--about-body-paper);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 40px 0 0;
  padding: 0;
  background: var(--line-dark-soft);
  border-top: 1px solid var(--line-dark);
  border-bottom: 1px solid var(--line-dark);
}

.page-about .hero-stat {
  background: var(--ink-900);
  padding: 18px 16px 20px;
}

.page-about .hero-stat dt {
  margin-bottom: 10px;
  font-size: var(--fs-14);
  color: var(--slate);
  letter-spacing: .04em;
}

.page-about .hero-stat dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: .02em;
  color: var(--amber);
}

.page-about .hero-stat .unit {
  margin-left: 6px;
  font-size: 13px;
  font-weight: 400;
  letter-spacing: .04em;
  color: var(--slate);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-block {
  padding: 56px 0;
}

.page-about .about-block--paper {
  background: var(--paper);
  color: var(--black);
}

.page-about .about-block--ink {
  background: var(--ink-900);
  color: var(--paper);
}

.page-about .about-chapter-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .about-chapter-side {
  border-top: 2px solid var(--amber);
  padding-top: 16px;
}

.page-about .about-block--paper .about-chapter-side {
  border-top-color: var(--amber-deep);
}

.page-about .section-num {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .16em;
  color: var(--amber);
}

.page-about .about-block--paper .section-num {
  color: var(--amber-deep);
}

.page-about .about-chapter-side h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 26px;
  line-height: 1.24;
  letter-spacing: -.01em;
}

.page-about .about-chapter-body {
  padding-top: 4px;
}

.page-about .about-chapter-body p {
  margin: 0 0 1.15em;
  max-width: 62ch;
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--about-body-ink);
}

.page-about .about-block--ink .about-chapter-body p {
  color: var(--about-body-paper);
}

.page-about .about-chapter-body p:last-child {
  margin-bottom: 0;
}

.page-about .about-chapter-body b {
  color: var(--amber-deep);
  font-weight: 700;
}

/* ---------- 图文 ---------- */
.page-about .about-figure {
  margin: 36px 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line-light);
}

.page-about .about-block--ink .about-figure img {
  border-color: var(--line-dark);
}

.page-about .caption {
  display: block;
  margin-top: 12px;
  font-size: var(--fs-14);
  line-height: 1.7;
}

.page-about .about-block--paper .caption {
  color: rgba(16, 22, 28, .6);
}

.page-about .about-block--ink .caption {
  color: var(--slate);
}

/* ---------- 发展节点 ---------- */
.page-about .timeline {
  list-style: none;
  margin: 40px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-dark);
}

.page-about .timeline-item {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: 6px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line-dark-soft);
}

.page-about .timeline-year {
  display: block;
  font-family: var(--font-mono);
  font-size: 21px;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: .04em;
  color: var(--amber);
}

.page-about .timeline-body h3 {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  color: var(--paper);
}

.page-about .timeline-body p {
  margin: 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--about-body-paper);
}

/* ---------- 访问四步 ---------- */
.page-about .journey {
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: 42px 0 0;
  padding: 0;
  background: var(--line-light);
  border: 1px solid var(--line-light);
}

.page-about .journey-step {
  background: var(--about-card);
  padding: 26px 20px 28px;
}

.page-about .journey-num {
  display: block;
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .18em;
  color: var(--amber-deep);
}

.page-about .journey-step h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--black);
}

.page-about .journey-step p {
  margin: 0 0 10px;
  font-size: 15.5px;
  line-height: 1.76;
  color: var(--about-body-ink);
}

.page-about .journey-step .journey-gain {
  margin: 14px 0 0;
  padding-top: 12px;
  border-top: 1px dashed rgba(138, 90, 6, .38);
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--amber-deep);
}

/* ---------- 更新节奏 ---------- */
.page-about .upkeep-top {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  align-items: center;
}

.page-about .upkeep-copy h2 {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 27px;
  line-height: 1.24;
  letter-spacing: -.01em;
}

.page-about .upkeep-copy .lede {
  margin: 0;
  max-width: 58ch;
  font-size: var(--fs-17);
  line-height: 1.8;
  color: var(--about-body-paper);
}

.page-about .upkeep-figure {
  margin: 0;
}

.page-about .upkeep-figure img {
  display: block;
  width: 100%;
  max-width: 420px;
  height: auto;
  margin: 0 auto;
  border: 1px solid var(--line-dark);
}

.page-about .upkeep-accordion {
  margin-top: 40px;
  border-top: 1px solid var(--line-dark);
}

.page-about .accordion-item {
  border-bottom: 1px solid var(--line-dark-soft);
}

.page-about .accordion-trigger {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr) 18px;
  align-items: center;
  gap: 14px;
  width: 100%;
  padding: 20px 0;
  background: transparent;
  border: 0;
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 17px;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
}

.page-about .accordion-trigger:focus-visible {
  outline: 2px solid var(--amber);
  outline-offset: 4px;
}

.page-about .acc-index {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .08em;
  color: var(--amber);
}

.page-about .acc-label {
  transition: color .18s var(--ease);
}

.page-about .accordion-trigger:hover .acc-label {
  color: var(--amber);
}

.page-about .acc-mark {
  position: relative;
  justify-self: end;
  width: 14px;
  height: 14px;
}

.page-about .acc-mark::before,
.page-about .acc-mark::after {
  content: "";
  position: absolute;
  background: var(--amber);
}

.page-about .acc-mark::before {
  left: 0;
  top: 6.5px;
  width: 14px;
  height: 1.5px;
}

.page-about .acc-mark::after {
  left: 6.5px;
  top: 0;
  width: 1.5px;
  height: 14px;
  transition: transform .22s var(--ease), opacity .22s var(--ease);
}

.page-about .accordion-trigger[aria-expanded="true"] .acc-mark::after {
  transform: scaleY(0);
  opacity: 0;
}

.page-about .accordion-panel {
  overflow: hidden;
}

.page-about .accordion-body {
  padding: 0 0 24px 54px;
}

.page-about .accordion-body p {
  margin: 0;
  max-width: 64ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--about-body-paper);
}

/* ---------- 适用人群 ---------- */
.page-about .audience {
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: 40px 0 0;
  padding: 0;
  background: var(--line-light);
  border-top: 1px solid var(--line-light);
  border-bottom: 1px solid var(--line-light);
}

.page-about .audience-item {
  background: var(--paper);
  padding: 24px 20px 26px;
  border-left: 3px solid var(--paper-2);
  transition: border-color .2s var(--ease);
}

.page-about .audience-item:hover {
  border-left-color: var(--amber);
}

.page-about .audience-item h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--black);
}

.page-about .audience-item p {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.78;
  color: var(--about-body-ink);
}

.page-about .audience-item b {
  color: var(--amber-deep);
  font-weight: 700;
}

/* ---------- 联系 ---------- */
.page-about .contact-lines {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-dark-soft);
}

.page-about .contact-line {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line-dark-soft);
  font-size: 16px;
  line-height: 1.7;
  color: var(--paper);
  word-break: break-word;
}

.page-about .contact-key {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .1em;
  color: var(--amber);
}

.page-about .contact-note {
  margin: 16px 0 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--slate);
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero {
    padding: 28px 0 72px;
  }

  .page-about .about-hero h1 {
    font-size: 46px;
  }

  .page-about .hero-stat {
    padding: 22px 20px 24px;
  }

  .page-about .about-block {
    padding: 72px 0;
  }

  .page-about .about-chapter-side h2 {
    font-size: 30px;
  }

  .page-about .upkeep-copy h2 {
    font-size: 32px;
  }

  .page-about .journey {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .audience {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .contact-line {
    grid-template-columns: 92px minmax(0, 1fr);
    gap: 16px;
    align-items: baseline;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 32px 0 96px;
  }

  .page-about .about-hero h1 {
    font-size: 56px;
  }

  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 6fr);
    align-items: end;
    gap: 64px;
    margin-top: 60px;
  }

  .page-about .hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    margin-top: 64px;
  }

  .page-about .about-block {
    padding: 96px 0;
  }

  .page-about .about-chapter-grid {
    grid-template-columns: minmax(0, 38fr) minmax(0, 62fr);
    gap: 0 56px;
  }

  .page-about .about-chapter-side {
    align-self: start;
    position: sticky;
    top: 88px;
  }

  .page-about .about-chapter-side h2 {
    font-size: 32px;
  }

  .page-about .about-figure {
    margin-top: 48px;
  }

  .page-about .timeline {
    margin-top: 48px;
  }

  .page-about .timeline-item {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: 0 36px;
    padding: 26px 0 26px 26px;
  }

  .page-about .timeline-item::before {
    content: "";
    position: absolute;
    left: 0;
    top: 31px;
    width: 9px;
    height: 9px;
    background: var(--amber);
  }

  .page-about .timeline-item::after {
    content: "";
    position: absolute;
    left: 4px;
    top: 40px;
    bottom: 0;
    width: 1px;
    background: var(--line-dark-soft);
  }

  .page-about .timeline-item:last-child::after {
    display: none;
  }

  .page-about .upkeep-top {
    grid-template-columns: minmax(0, 62fr) minmax(0, 38fr);
    gap: 0 64px;
    align-items: center;
  }

  .page-about .upkeep-figure img {
    max-width: 100%;
    margin: 0;
  }

  .page-about .upkeep-accordion {
    margin-top: 56px;
  }

  .page-about .accordion-trigger {
    grid-template-columns: 56px minmax(0, 1fr) 18px;
    padding: 22px 0;
    font-size: 18px;
  }

  .page-about .accordion-body {
    padding-left: 70px;
  }
}

@media (min-width: 1100px) {
  .page-about .journey {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .timeline-item {
    grid-template-columns: 172px minmax(0, 1fr);
  }

  .page-about .timeline-year {
    font-size: 23px;
  }
}